Antifouling coating for wood.



No. 629,427. Patented July 25, I899.

a. n. COLEMAN. ANTIFOULING COATING FOR'WOOD.

(Application filed Nov. 9, 1898.)

(No Model.)

- UNITED STATES PATENT OFFIC GEOI tGE D. COLEMAN, OF BRIDGEWATER, MASSACHUSETTS.

ANTIFOU LING COATING FOR WOO-D.

SPECIFICATION forming part of Letters Patent No. 629,427, dated July 25,1899.

Application filed November 9, 1898.

State of Massachusetts, have invented certain new and useful Improvements in Antifouling Coatings for Wood; and I do hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of my invention is to produce an efficient antifouling coating for wood, and especially an antifoulin g coating for the wooden bottoms of sea-going vessels and for the submerged portions of docks and the like, which are in contact'with the sea-water and which in the absence of some antifoulin g coating are rapidly covered with marine growths, especially in the tropical seas, which in the case of vessels materially diminishes their speed.

In the drawings accompanying this specification, illustrating the preferred form of my invention, and in which like reference-letters refer to like parts throughout, Figure 1 is a face view, on a very much enlarged scale, of a portion of a piece of wood provided with indentations. Fig. 2 represents across-section, on the same scale, of a portion of a piece of wood with my antifouling coating applied thereto. 1, p

Heretofore it has been customary to coat the bottoms of ships with sheet-copper, which being exposed to the action of the sea-water is oxidized on its outer surface, and the oxids thus formed change to various other salts of copper, which being highly poisonous in their nature prevent the accumulation of marine growthsthereon. Myinventioncontemplates a substitute for such copper surface which shall be easily applied,,efficiently held, and at the same time made very much more cheaply than the sheet-copper coating.

In carrying my invention into practice I apply to the surface of the wood comminuted copper, which is embedded therein. 'lheportions of the particles of comminuted copper which remain exposed upon the surface of the wood become oxidized by contact with the sea-water, and the oxids thus formed graduall ychange into other salts of copper, which Serial No- 695,94=8. (No specimens.)

efficiently prevent the accumulation of marine growths upon the surface of the wood.

While I have referred to com minuted copper as the material to be applied to and embedded in the surface of the wood, I do not desire to limit myself specifically to that metal,

loy of copper or other metal which upon exposure to the action of sea-Water becomes rapidly coated with salts poisonous to marine growths is within the purview of my invention. So when I use the term copper I would have it understood that I may use that metal or its alloys or any other metal or alloy which decomposes in like manner.

The comminuted copper may be applied to the surface of the wood by being laid thereon and driven by suitable tools into the same. I prefer, however, to apply the comminuted copper to the surface of the wood afterthe same shall have been subjected to the action of tools which shall out numerous indentations through the outer surface of the wood. Into these indentations I then drive the comminuted copper. As is well known, when dry wood isindented and afterward moistened a swelling of the fiber of the wood tends to obliterate the indentations by bringing the fiber to the surface again, so if the copface of the wood it might be that when the wood was moistened by immersion in water the particles of copper might be thrown 01f. In order to prevent this shedding of the particles of copper, I consider that it is preferable previously to cut indentations in the wood. By this means the continuity of the surface fiber of the wood is destroyed, and when the copperisembeddedin thepreviouslyformed indentations it will be securely held by the wood when the wood shall be moistened, because the swelling of the fiber by reason of the moisture will not act to shed or throw off the particles of copper, but the fiber will swell around them and hold them securely in the surface of the wood.

per should completely cover the entire surface of the wood, for the reason'that as the copper decomposes under the action of the sea-water the salts thereby formed will spread around each particle of copper upon the contiguous as it will be readily understood that any al-' per were merely driven into the smooth sur-' It is not necessary that the particles of copsurfaces of the wood, covering the whole sur: facewithacoating of poisonous salts, to which marine growths will not attach themselves.

Although it is quite practical and within the purview of my invention to apply the comminuted copper directly to the indented surface of the wood and to hammer the same thereinto, I have found it convenient and preferable to apply the comminuted copper to the surface of the wood in a paste soluble in water. By this means I am enabled to apply tothe surface of the wood a coating of comminuted copper in position to be driven into the surface of the wood by a hammer or any other suitable tool. After the hammering process is completed the soluble paste .may be washed off, and thus afiords a ready means of examining the surface and determining as thework progresses the closeness of the particles of copper toeach other.

In" case the comminuted copper is applieddirectly to the wood without the use of a j of the poisonous salts of copper may be any paste or after'the paste has been washed off and the surface of the wood is exposed it will 25 be found to be provided with a coating of manysmall pieces of copper embedded in the wood. This coating is an efficient one for theprevention of accumulation of marine growths; but I prefer at this stage tocoat the whole with a paint composed of the poisonous salts of copper, which, paint efficiently fills the interstices between the small particles of copper and at the same time promotes the decomposition of these particles when subjected to the action of sea-water. This paint of. the well-known antifouling paints or a paint entirely :of such poisonous salts of copper or any material which will become poison-- ous on exposure to sea-water in the presence of copper and any desired volatile binder which willserve to tie-the substance together untilrit shall become hard and dry. be applied with a brush or with a trowehdepending upon its consistency and the amount desired to be applied, and the surface may be jnuted copper will of course gradually be abraded and washed off by the action of the water; but the particles of copper being at the same time subjected to the action of the g sea-water will be decomposed and serve to renew the antifouling substance lost from between the particles of comminuted copper.

In Fig. 1 of the drawings I have illustrated the particles of comminuted copper.

It may consists of comminuted copper orother suita portion of the surface of the wood provided with indentations A to receive the particles of comminuted copper, and in Fig. 2 I have shown a cross-section of a portion of a piece of wood B through the coating, wherein O indicates the particlesof comminuted copper and D indicates the surface coating of antifouling substance in the interstices between This figure clearly shows, on a much -enlarged scale, the embedding of the particles of copper in the surface of the wood.

I am aware that it is old to apply a coating to the bottoms of ships which consists of a paints, such as red lead, having suspended therein particles of comminut'edcopper; but it will be observed that such coating is radically different from the coating which I apply, and, moreover, it is liableto bechipped or flaked off from the bottom of the vessel by rine growths. In other words,the com minuted copper applied according to my invention makes a very much more durable coating by reason of its beingembedded in the surface of the wood and not merely attached thereto by force of cohesion and having the further advantage of renewing itself by decomposition of the metallic copper.

Having thus described my inven tion, I claim as broadly novel and desire to secure --byLetters Patent of the United States 1. An antifouling coating for wood which able substance embedded in the'surface of the wood, substantially as described.

2. An antifouling coating for wood which consists of comminuted copper orother suitable substance embedded in the surface of the wood and a surface coating of antifouling substance in the interstices between the embedded particles of com minuted substance, substantially as described.

In testimonywhereof I affix my signature in presence of two witnesses.

GEORGE Di GOLEMAN.

Witnesses:

T. HART ANDERSON, IIoRAoE VAN EVEREN. 

